Hair straightener



FIG. 1 is a perspective view of a hair straightener;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the figure drawings are for the purpose of illustrating portions of the hair straightener which form no part of the claimed design. 

CLAIM The ornamental design for a hair straightener, as shown and described. 